jsonUtils&&Json、Xml转换工具Jackson使用

1.jsonUtils

package com.icil.utils;

import java.util.List;

import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.JavaType;
import com.fasterxml.jackson.databind.ObjectMapper;
/**

  需要的依赖（jar）

   <!-- Jackson Json处理工具包   用于处理bean 到 json json dao  bean   -->
            <dependency>
                <groupId>com.fasterxml.jackson.core</groupId>
                <artifactId>jackson-databind</artifactId>
                <version>2.4.2</version>
            </dependency>

 */

/**
 * 自定义响应结构(pojo to json to pojo)
 */
public class JsonUtils {

    // 定义jackson对象
    private static final ObjectMapper MAPPER = new ObjectMapper();

    /**
     * 将对象转换成json字符串。
     * <p>Title: pojoToJson</p>
     * <p>Description: </p>
     * @param data
     * @return
     */
    public static String objectToJson(Object data) {
        try {
            String string = MAPPER.writeValueAsString(data);
            return string;
        } catch (JsonProcessingException e) {
            e.printStackTrace();
        }
        return null;
    }

    /**
     * 将json结果集转化为对象
     *
     * @param jsonData json数据
     * @param clazz 对象中的object类型
     * @return
     */
    public static <T> T jsonToPojo(String jsonData, Class<T> beanType) {
        try {
            T t = MAPPER.readValue(jsonData, beanType);
            return t;
        } catch (Exception e) {
            e.printStackTrace();
        }
        return null;
    }

    /**
     * 将json数据转换成pojo对象list
     * <p>Title: jsonToList</p>
     * <p>Description: </p>
     * @param jsonData
     * @param beanType
     * @return
     */
    public static <T>List<T> jsonToList(String jsonData, Class<T> beanType) {
        JavaType javaType = MAPPER.getTypeFactory().constructParametricType(List.class, beanType);
        try {
            List<T> list = MAPPER.readValue(jsonData, javaType);
            return list;
        } catch (Exception e) {
            e.printStackTrace();
        }

        return null;
    }

}

package com.icil.esolution.utils;
import java.util.List;

import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.JavaType;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.google.gson.Gson;
import com.google.gson.reflect.TypeToken;

/**
 * 

* @ClassName: JsonUtils 

* @Description:json to bean   object to json 

* @author  Sea

* @date 24 Aug 2018 2:12:27 PM
*
 */
public class JsonUtils {

    // 定义jackson对象
    private static final ObjectMapper MAPPER = new ObjectMapper();

    /**
     * 将对象转换成json字符串。
     * <p>Title: pojoToJson</p>
     * <p>Description: </p>
     * @param data
     * @return
     */
    public static String objectToJson(Object data) {
        try {
            String string = MAPPER.writeValueAsString(data);
            return string;
        } catch (JsonProcessingException e) {
            e.printStackTrace();
        }
        return null;
    }

    /**
     * 将json结果集转化为对象
     *
     * @param jsonData json数据
     * @param clazz 对象中的object类型
     * @return
     */
    public static <T> T jsonToPojo(String jsonData, Class<T> beanType) {
        try {
            T t = MAPPER.readValue(jsonData, beanType);
            return t;
        } catch (Exception e) {
            e.printStackTrace();
        }
        return null;
    }

    /**
     * 将json数据转换成pojo对象list
     * <p>Title: jsonToList</p>
     * <p>Description: </p>
     * @param jsonData
     * @param beanType
     * @return
     */
    public static <T>List<T> jsonToList(String jsonData, Class<T> beanType) {
        JavaType javaType = MAPPER.getTypeFactory().constructParametricType(List.class, beanType);
        try {
            List<T> list = MAPPER.readValue(jsonData, javaType);
            return list;
        } catch (Exception e) {
            e.printStackTrace();
        }

        return null;
    }

    /**
     * 可以排除多余的字段,如json中包含字段"aa":"aa" 但是pojo中没有.
     * @param json
     * @param beanType
     * @return
     */
    public static <T>List<T> JsonTOList(String json, Class<T> beanType){
        Gson gson = new Gson();
        List<T> jsonToList =gson.fromJson(json, new TypeToken<List<T>>() {}.getType());
      return jsonToList;
    }

}

2.Java对象、Json、Xml转换工具Jackson使用 参考https://blog.csdn.net/Rongbo_J/article/details/47986121

依赖：

<!-- Jackson Json处理工具包 用于处理bean 到 json json dao bean -->
        <!-- https://mvnrepository.com/artifact/com.fasterxml.jackson.core/jackson-databind -->
        <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-databind</artifactId>
            <version>2.9.</version>
        </dependency>

        <!-- https://mvnrepository.com/artifact/com.fasterxml.jackson.core/jackson-core -->
       <!-- 转json 和json转bean用到-->
　　　　 <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-core</artifactId>
            <version>2.9.</version>
        </dependency>
        <!-- https://mvnrepository.com/artifact/com.fasterxml.jackson.dataformat/jackson-dataformat-xml -->
      <!-- 转xml 和xml转bean用到-->
      <dependency>
            <groupId>com.fasterxml.jackson.dataformat</groupId>
            <artifactId>jackson-dataformat-xml</artifactId>
            <version>2.9.</version>
        </dependency>

2.1.將Java对象转换为Json字符串：

@Test
    public void testGenJson()
    {
        ObjectMapper objMapper = new ObjectMapper();
        Book book = new Book("Think in Java",);
        try {
            jsonGen = objMapper.getJsonFactory().createJsonGenerator(System.out,JsonEncoding.UTF8);
            jsonGen.writeObject(book);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

2.2將Json字符串转为Java对象：

     /*
     * Java对象转xml
     */
    @Test
    public void testGenXml()
    {
        XmlMapper xmlMapper = new XmlMapper();

        Book book = new Book("Think in Java",);
        try {
            String xmlStr =  xmlMapper.writeValueAsString(book);
            System.out.println(xmlStr);
        } catch (JsonProcessingException e) {
            e.printStackTrace();
        }
    }

 /*
     * Json转Java对象
     */
    @Test
    public void testGenObjByJson()
    {
        ObjectMapper objMapper = new ObjectMapper();
        String json = "{\"name\":\"Think in Java\",\"price\":100}";
        try {
            Book book = objMapper.readValue(json, Book.class);
            System.out.println(book);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

2.3將Java对象转为Xml格式

 /*
     * Java对象转xml
     */
    @Test
    public void testGenXml()
    {
        XmlMapper xmlMapper = new XmlMapper();

        Book book = new Book("Think in Java",);
        try {
            String xmlStr =  xmlMapper.writeValueAsString(book);
            System.out.println(xmlStr);
        } catch (JsonProcessingException e) {
            e.printStackTrace();
        }
    }

4.將xml格式字符串转为Java对象

  /*
     * xml转Java对象
     */
    @Test
    public void testGenObjByXml()
    {
        XmlMapper xmlMapper = new XmlMapper();
        String xmlStr = "<Book><name>Think in Java</name><price>100</price></Book>";
        try {
            Book book = xmlMapper.readValue(xmlStr, Book.class);
            System.out.println(book);
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

    }